Backlash resisting locking setscrew



-1 ,1944. Gum-5* 2 ,355',901.

BACKLASH RESISTING LOCKING SET SCREW Original Filed Dec. 6, 1940 Fzy 111a? 0012 t or Hard? err 6 Be ede; 0:551:50 B y Robert Jflc ede, xcumqPatented Aug. 15, 1944 2,355,901 BACKLASH RESISTING LOCKING SETSCREWHerbert G.

Beede, deceased, late of Pawtucket,

R. L, by Robert J enks Beede, executor, Seekonk,

Mass., Inc., ware Original application Dec 368,884. Divided an 1943,Serial No. 494,052

4 Claims. (Cl. 151-32) This is a division of the application of HerbertG. Beede, No. 368,884, filed December 6 1940.

This invention of Herbert G. Beede, deceased, relates to improvements inback lash resisting locking set screws particularly of the general typeof locking set screw described in his copending application No. 368,414for Looking set screw, filed December 4, 1940, and illustratingadditional embodiments of the novel features claimed therein. Thepresent application is specifically directed to supplemental featuresincluding fea tures tending to prevent backlash which may be employed insuch'a locking set screw, particu larly one having a wedge point toengage with a complemental deformation or cavity in the mov able member.

An object of the present invention is to so design such a wedge pointlocking set screw that the parts thereof may be relatively adjusted toreduce play in the locking action of the set screw on the retaining andmovable members.

Further features of this invention relate to various modifications ofthe structural features of the improved set screw shown in this and saidparent application No. 368,414 to eliminate play or backlash.

These and such other objects of this invention as may hereinafter appearwill be best understood from a description of the accompanying drawingwhich illustrates various embodiments thereof.

In the drawing,

Fig. 1 is a sectional view of a. first modification of a locking setscrew showing the retainin or first member in section, the bolt memberof the set screw in axial section and the stem member and locking meansin elevation.

Fig. l is a plan View of the first modification of locking set screw.

Fig. 1 is a reverse plan view of the first modification of locking setscrew.

Fig. 2 is a sectional view similar to Fig. l of a second modification ofthe invention with the retaining member omitted having a differentmodification of means adapted to wedgedly engage a preformed deformationin the movable member, showing the bolt portion of the set screw inaxial section and the stem member and locking means in elevation andillustrating the improved type of play prevention means of Fig. 1, andanother type of locking and jacking means.

Fig. 2 is a plan view of the modification of locking set screw shown inFig. 2.

Fig. 2 is a reverse plan view of the modification of locking set screwshown in Fig. 2.

assig'nor to Pantex Pressing Machine, Central Falls, R. 1., acorporation of Delaember 6, 1940, Serial No. d this application July 9,

Fig. 3 is a sectional view similar to Fig. 1 of a third modification ofthe invention with the bore of the bolt member only extending part ofthe distance downwards from the upper end thereof and defining therecess circular in cross-section at a spaced distance from the lower endof the bolt member instead of at the lower end as shown; in Figs. 1 and2 and with-the cooperating conical surface of the stem member similarlyraised from the lower end of the stem member, showing the bolt member ofthe set screw in axial section and the stem member and locking means inelevation, said set screw being :similar in other respects to the setscrew shown in Fig. 1.

Fig. 3 is a plan view of the third modification of locking set screw.- I

Fig. 3 is a reverse plan view of the third modification shown in Fig. 3.

In the drawing, wherein like characters of reference generally indicatelike parts throughout, I 0 generally indicates a locking set screwsimilar to those shown in said applications.

While his improved type of set screw l 0 may be employed for locking anytype of a relatively movable second member l8 in adjusted positionrelative to a retaining or first member Is, he has illustrated it in thedrawing as employed to lock a movable shaft or second member I 8 in a.bore M in a housing or first member IS, the set screw having a threadedshank 22 being inserted within a threaded set screw hole l2 in saidhousing or first member 16. In all embodiments of the invention shown,the shank 22 comprises the usual bolt member 22 of a set screw and isprovided with a hollow preferably smooth circular axial bore 28 and witha standard type of turning head 26 or other suitable turning means. Theinner looking stem member 24 extends through said hol low bolt shankmember bore 28 and has an end portion 32 with an upper portion 34 ofgreater area than said bolt member bore 28 below said bore to positivelylimit the axial outward movement of said stem member 24 relative to saidbolt member 22, and with means 36 on the lower end thereof fornon-rotatably engaging said movable member IS in said retaining memberrecess I 4 to restrain relative movement between said relatively movablesecond and retaining first members. He also employs means 42 for lockingsaid bolt member 22 to said inner stem member 24 with said means 36 onthe end portion 32 of said stem member thereof non-rotatably engagingsaid second movable member l8 in the desired adjusted manner.

Any suitable means 36 on the lower end of said end portion 34 fornon-rotatably engaging said movable second member to restrain relativemovement between said movable second and retaining first members may beemployed, and he has shown in the drawing two types of such means,although the features of the present invention may be employed with anyof the three species described in said other application, namely, (1)means on said end portion to positively mate with preformed means onsaid movable member, as in the modification shown in Figs. 1, 2 and 3;and (2) a pointed projection on said end portion adapted to positivelybite into said movable second member to form its complementally shapedinterlocking portion thereon while being inserted. This feature (2) isalso partially shown in the modifications shown in Figs. 1, 2 and 3,wherein the projection is of a different shape from its cooperatingcavity to deform its complementally shaped interlocking portion thereonwhile being inserted to also-provide a wedging locking action in themodfiications shown in Figs. 1, 2 and '3.

In the modification of his invention shown in Fig. 1 he has provided theportion 36 shown therein as of truncated pyramidal shape to fit into acylindrical radial hol 38 in said shaft, the edges 39 of said pyramidbiting into the edge of the side wall of said cylinder to wedgedlyengage said point 36 in the cooperating recesses 35 formed in said edge.In the modification of the invention shown in' Fig. 2, the portion 36shown therein comprises a frustro conical lower end 36 adapted tocontact the edge of the side wall of a cylindrical radial hole 38 insaid shaft [8 to positively preventrelative movement between saidmovable member l8 and retaining member [6.

- In the modification of the invention shown in Fig. 3 he has shown apyramidal point 36 similar to that shown in Fig. 1 adapted to fit into acylindrical radial hole 38 in the shaft.

Any suitable type of means 42 for locking the rotatable bolt member 22to said stem member 24 with the engaging means 36 non-rotatably engagingsaid movable second member in the desired adjusted manner may beemployed. In the modifications shown in Figs. 1 and 3, he hasillustrated the preferred type of locking means consisting of aplurality of diametric slits 44 in the upper surface of the turning head26 of the bolt member 22 and he preferably provides a diametric hole 45adjacent the outer end of the stem member. After the shaped engagingmeans 36 of the end portion 32 of the stem member has engaged the shaft18, a cotter pin 48 may be inserted through the most adjacent diametricslit 44 in the turning head 26 and the diametric hole 46 in said stemmember for this purpose aligned therewith. For the purpose of relativelturning th stern member 24 to said bolt member 22, the outer end of thestem member may be provided with suitable means for turning it, such asthe diametric slot 50, shown in Fig. 2, to receive the end of a screwdriver therein. If desired, however, a separate external head of anystandard type known in the art may be employed. In place of thepreferred type of lock.- ing means 42, any suitable type of lockingmeans may be employed, such as the lock washer 42 of standardconstruction shown in Fig. 2, which may be inserted axially between thehead 26 of the bolt member 22 and the jack nut Bil shown therein,although a lock washer 4? may be emof the bolt member as shown in Fig. 3and the upper portion 34 of'said portion 32 of greater area than saidbolt member bore 28 may be provided with a complementally shaped uppersurface 64 to wedgedly engage the surface 62 of said bore 28 to preventplay. It is obvious that with this construction the cooperating taperedsurfaces 62 and 64 will engage against each other to prevent playbetween the bolt member 22 and the stem member 24, thereby preventingplay between such members. In the embodiment shown in Fig. 3, however,the bore 28 terminates at a subtstantial distance above the lower end ofthe bolt member and defines the enlarged tapered recess 62 circular incross section in said hollow bolt. In this embodiment the cooperatingconical surface 64 of the stem member is correspondingly raised from thelower end of the bolt member to engagewith said recess 62 to preventplay. If, however, the wedge points 35 and 36 be also employedto-positively engage a shaped cavity, whether preformed or formed by theinsertion of the stem member 24, play will also be.- substantiallyeliminated between said stem member 24 and movable member' 18. It isapparent, therefore, that if both types of means to prevent play, namely(1) between the bolt member and the stem member and (2) between thepoint of the stem member and the movable member be employed, play andbacklash will be substantially eliminated, as in the modifications shownin Figs. 1-3.

To employ the set screw, it is merely necessary to screw the set screw10 within the hole [2 until the engaging means 36 thereof firmly abutsthe desired portion of the movable member l8 no matter what thecooperating shapes of said engaging means 36 and movable member may be.If desired, as shown in Fig. 2, a slot 5!] may be provided in the outerend of the stem member to rotate the stem member 24 within the hollowbolt 22. To prepare for locking, if necessary, the head 26 may befurther turned until a selected channel 44 in said turning head 26 isbrought into alignment with the diametric hole 46 on the stem. To lock,the locking pin 48 may then, in the modification shown in Figs. 1 and 3,be inserted through said aligned channel 44 and diametric hole 46 topermanently lock the set screw in the desired adjusted position with theengaging means thereof engaging said movable member in the desiredadjusted manner. The modification of the invention shown in Fig. 2 maybe locked on suitable turning movement of the jack nut 60, the lockwasher 42 becoming automatically locked as the jack nut is turnedrelative to said turning head 26. It is apparent that turning theturning head automatically brings the conical surfaces 62 and 64 intointimate contact throughout the periphery thereof to prevent backlashsubstantially at the moment that the engaging means 36 engages themovable member I8, the friction between these two surfaces, however,being increased if an extra turning movement is given for the purpose ofaligning or looking the locking means.

To remove the set screw,"in the modifications shown in Figs. 1 and 3, itis merely necessary to release the locking means by withdrawing the pin48 and unscrewingthe turning head 26 which will abut the enlargedjacking head 60 of the stem member which will function to pull thepointed end 36 of the stem member out of engagement with its cooperatingcavity lit in the movable member 18. In the modification of theinvention shown in Fig. 2, the jack nut 60 may be inserted on saidthreaded end 65 of the stem member merely for the purpose of removingthe set screw by providing means for positively pulling the set screwpoint 36 out of engagement with its cooperating cavity 38 on the shaftl8. For this purpose the jack nut 60 is only screwed on said threadedend until it is adjacent to but not touching the upper surface of theturning head 26 so that it will not function as a lock nut therefor. Thesame wrench may be employed to turn the turning head 26 and also turnthe jack nut 60 to partially simultaneously unscrew the set screw andprovide jacking means to positively pull the pointed end 36 of the stemmember out of engagement with its cooperating cavity 38 in the shaftmember l8 on a later tightening of the jack nut 60 in the mannerhitherto described, the cooperating threads 65 on the outer periphery ofthe stem member 24 and the threads on the inner periphery of the jacknut 60 cooperating as inclined planes to effect this pulling movement.If the jack nut 60 be also employed as a portion of the locking means,as shown in Fig. 2, it is obvious that it will have to be initiallyunscrewed on said threads 65 to be moved out of contact with the lockwasher 42 to release said locking means prior to the actuation of saidlock nut 60 by a suitable wrench or other means, said lock nut 60 thenfunctioning as a jack nut to positively pull the pointed end 36 of thestem member out of engagement with its cooperating cavity 38 in themovable member in similar manner as in the other modifications. It isalso obvious that the jack nut 60 will function in the manner explainedto release the backlash preventing means, comprising the contactingconical surfaces 62 and E4 of the modifications shown in Figs. 1, 2 and3, as the jack functions to release the pointed end 36 from itscooperating cavity 38.

It is apparent, therefore, that he has provided certain novelmodifications employing the general principles of the set screw shown inhis companion application heretofore referred to, particularly adaptedto positively engage the movable member with a wedging action and to provide means to prevent play and backlash between the parts thereof andthe movable member and that he has also provided, preferably inassociation therewith, a suitable means effective on withdrawal of saidset screw to positively pull said movable or pointed engaging means 36away from engagement with said movable member and at the same timerelease said play preventing means with the advantages described above.

It is understood that his invention is not limited to the specificmodifications shown or described and that various deviations may be madetherefrom without departing from the spirit and scope of the appendedclaims.

What he claims is:

1. A set screw for insertion within a threaded set screw hole in a firstmember extending to a second member movable relative to said firstmember, comprising a threaded bolt member recess'to prevent play'andhaving means on thelower end thereof for non-rotatable engagement withsaid second member and means for locking said bolt member to said stemmember against relative rotative movement, said stem member having meansassociated with the upper end thereof of greater area than the bore ofthe bolt member to release said cooperating engaging surfaces onunscrewing of said bolt member.

2. A set screw for insertion within a threaded set screw hole in a firstmember extending to a second member movable relative to said firstmember, comprising a threaded bolt member having a smooth circular borewith a conical surface defining an enlarged recess circular incross-section and turning means, a smooth stem member extending throughsaid bore and having a portion of greater area than said bore having acooperating conical surface engageable with said recess to prevent playand having a projecting portion at the lower end thereof to fit into acavity in said second member with a wedging action and means for lockingsaid bolt member to said stem member against relative rotative movement,said stem number member having means associated with the upper endthereof of greater area than the bore of the bolt member to release saidcooperating engaging surfaces on unscrewing of said bolt member.

3. A set screw for insertion within a threaded set screw hole in a firstmember extending to a second member movable relative to said firstmember, comprising a threaded bolt member having a smooth circular borewith a conical surface defining an enlarged recess circular incrosssection at the lower end thereof and turning means, a smooth stemmember extending through said bore and having a portion of greater areathan said bore beyond the threaded end of said bolt member, said endportion having its largest effective diameter less than the continuouseffective diameter of the set screw hole so that it may be freelyrotated therein and having a cooperating conical surface engageable withsaid recess to prevent play and having means on the lower end thereoffor non-rotatable engagement with said second member and means forlocking said bolt member to said stem member against relative rotativemovement, said stem number member having means associated with the upperend thereof of greater area than the bore of the bolt member to releasesaid cooperating engaging surfaces on unscrewing of said bolt member.

4. A set screw for insertion within a threaded set screw hole in a firstmember extending to a second member movable relative to said firstmember, comprising a threaded bolt member having a smooth circular borewith a conical surface defining an enlarged recess circular incross-section at the lower end thereof and turning means, a smooth stemmember extending through said bore and having a portion of greater areathan said bore beyond the threaded end of said bolt member, said endportion having its largest effective diameter less than the continuouseffective diameter of the set screw hole so that it may be freelyrotated therein and havin a cooperating conical surface engageable withsaid recess to prevent play and having aprojecting portion at the lowerend thereof to fit into a cavity in said second member with a wedgingaction and means for locking said bolt member to said stem memberagainst relative rotative movement. saidstem -mem ber having meansassociated with the upper end thereof of greater area than the bore ofthe bolt member to release said cooperating engaging surfaces onunscrewing of said bolt member.

' ROBERT JENKS BEEDE,

5 Executor of the Estate of Herbert G. Beede, De-

ceased.

